A data processing system, such as a computer, is commonly used to store large amounts of information. Typically, the information is arranged in files with each file consisting of a block of information stored on a mass memory of the computer. The block of information may be individually accessed by a user.
The files are organized in a file system, which is controlled by an operating system of the computer. Substantially all the file systems known in the art have a hierarchical structure. Particularly, the files are included in containers which are often generally referred to as folders or directories. The folders are then linked in a tree, starling from a root folder defining a physical or logical device of the computer.
The file system facilitates the logical management of the files on the computer. Indeed, first of all a name of each file provides some sort of information about its characteristics. Moreover, all the files in a particular folder are likely to share common characteristics defining a corresponding category in some way identified by a name of the folder. Different levels of categories for the files may also be defined by the hierarchy of the folders. For example, it is possible to have a folder for all the customers, with further folders depending thereon for specific customers, each one including all the files relating to a corresponding customer with each file storing a specific communication with the customer.
In this scheme, the characteristics of the files may only be defined in a completely informal manner (according to the names of the files and the folders). Therefore, this information generally cannot be leveraged by software applications. Moreover, the organization of the files in the folders, once a specific hierarchy has been selected, is quite rigid and difficult to change. Particularly, each file belongs to a single folder.
It is possible to create a link to the same file into other folders. However, this mechanism only allows adding further characteristics to the file (according to the names of the other folders), breaks the concept of uniqueness of the files and makes the organization of the files very difficult to manage.